KornShell Boolean Conditional Logic

Question

I am a little confused with this KornShell (ksh) script I am writing, mostly with booleans and conditionals.

So the first part of my script I have catme and wcme both set to either true or false. This part is working fine, as I have tried echoing them and they produce the expected results. Later on, I have this code:

if [[ $catme ]] ; then some commands fi

And I repeat this with wcme. However, unexpectedly, no matter what wcme and catme are, the commands inside my if statement are executed.

Is this a syntax error? I have tried [[ $catme -eq true ]] but that does not seem to work either. Could someone point me in the right direction?

gahooa · Accepted Answer · 2011-01-28 03:23:35Z

test and [ are the same thing. You need to get rid of the test command from your if statement, so it would look like this:

if $catme; then some commands fi

Type man test to get more info.

For example:

$ v=true $ $v $ if $v; then > echo "PRINTED" > fi PRINTED $ v=false $ if $v; then > echo "PRINTED" > fi $

asoundmove · Accepted Answer · 2011-01-28 03:32:29Z

You can also try the trial and error method:

if [[ true ]]; then echo +true; else echo -false; fi +true if [[ false ]]; then echo +true; else echo -false; fi +true if [[ 0 ]]; then echo +true; else echo -false; fi +true if [[ -1 ]]; then echo +true; else echo -false; fi +true if (( -1 )); then echo +true; else echo -false; fi +true if (( 0 )); then echo +true; else echo -false; fi -false if (( 1 )); then echo +true; else echo -false; fi +true if [[ true == false ]]; then echo +true; else echo -false; fi -false if [[ true == true ]]; then echo +true; else echo -false; fi +true if true; then echo +true; else echo -false; fi +true if false; then echo +true; else echo -false; fi -false

asoundmove · Accepted Answer · 2011-01-28 03:27:46Z

0

Try [[ $catme == true ]] instead.

Or better still, gahooa's answer is pretty good.

answered Jan 28, 2011 at 3:27

asoundmove

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